Field of the Invention
The present invention relates to an image display apparatus and a method for controlling the same.
Description of the Related Art
There are fine particles known by the name of quantum dots. Quantum dots are semiconductor fine particles having a size (particle diameter) of several nm to several tens of nm. In a case where light is irradiated to the quantum dots, the quantum dots are excited and emit light. The wavelength of the light emitted from the quantum dots depends on the size of the quantum dots, which means that by controlling the size of the quantum dots, it is possible to obtain light having a high-purity color. The “light having a high-purity color” can in other words be expressed as “light having a sharp peak spectrum.” In this regard, a liquid-crystal display apparatus using quantum dots has been proposed (Japanese Patent Application Laid-open No. 2012-22028). A liquid-crystal display apparatus is an image display apparatus having a backlight module and a liquid-crystal panel. The liquid-crystal display apparatus disclosed in Japanese Patent Application Laid-open No. 2012-22028 uses a conversion member that includes quantum dots. The conversion member emits a part of light from the light sources of the backlight module to the liquid-crystal panel through converting same using the quantum dots, and emits a part of the light from the light sources without converting same.
In the backlight module of a liquid-crystal display apparatus, a plurality of light sources, which respectively correspond to a plurality of divided areas constituting an area of a screen, may be used. In relation to such a backlight module, the technique of local dimming control has been known (Japanese Patent Application Laid-open No. 2002-99250). In local dimming control, the light-emitting brightness of the plurality of light sources is individually controlled. The light-emitting brightness of the respective light sources is controlled based on, for example, input image data. Specifically, the light-emitting brightness of light sources corresponding to divided areas in which the input image data is dark is reduced to low light-emitting brightness. Further, in a case where the local dimming control is performed, image processing based on the light-emitting brightness of the respective light sources may be performed to the input image data.
However, in the above liquid-crystal display apparatus having the conversion member, color unevenness occurs in light from the conversion member due to the local dimming control. As a result, color unevenness occurs in a screen (color display unevenness).